Whole-system duct and dryer vent check with before-and-after photos - you see exactly what came out of your vents
That "$99 whole-house special" is a bait ad - the real number appears once they are in your hallway, or the "clean" is a shop-vac at the register. We photograph the inside of your ducts before and after instead.
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After
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AfterFast, Reliable Duct Sealing Across Ontario
Most duct sealing jobs in Ontario run $450 – $1,200 for a whole-house seal, depending on whether we’re working with original 1950s metal trunkwork or newer attic flex duct. We’re the Duct Sealing crew for Hollis Air Duct Cleaning, dispatching from our Inland Empire office to reach Ontario homes inside our quoted arrival window. If your registers blow dust every time the AC cycles, or your upstairs rooms never cool evenly, the problem is usually leaky joints and unsealed takeoffs, not your HVAC unit itself.
Ontario’s housing tells two stories. South of Holt Blvd and around the downtown core, thousands of post-WWII slab-foundation ranches still run on original round metal duct that was never wrapped or sealed at install. On the east side, 1980s – 2000s two-story subdivisions rely on attic flex duct that sags, kinks, and tears at elbows. Both leak conditioned air into attics and crawlspaces, but the fix for each is different. We price in writing before we touch anything, and every seal job carries our 365-Day Done Right Promise.
Call (361) 326-5060 for a free estimate. We’ll run a camera inspection, show you exactly where your system is bleeding air, and give you a flat price to fix it.
Why Hollis Air Duct Cleaning Is Ontario’s Preferred Duct Sealing Company
We’ve been doing this since 2004 as part of the Garrison Partners family, and our Ontario customers know the difference between a crew that tapes a few registers and calls it done versus one that crawls the full run. Our technicians are background-checked, uniformed, and expected to operate under The Garrison Code: arrive inside the window, price in writing, complete the job by the book, leave the site clean. No exceptions.
Phones are answered by a live person 24 hours a day, 7 days a week. No voicemail loops, no callback queues. When you schedule Duct Sealing in Ontario, you get a real arrival window and a written price that does not move at the door. If our seal fails within a year, we come back and make it right at no charge, including a free second visit. That’s the 365-Day Done Right Promise, backed in writing on every job.
Air Duct Sealing in Ontario
Air Duct Sealing in Ontario means finding every point where conditioned air escapes your ductwork and sealing it with mastic, mesh tape, and mechanical fasteners rated for your system’s pressure and temperature. For the 1950s – 1970s tracts south of Holt Blvd, this typically involves sealing original metal trunk joints that have been open for 60-plus years, then re-wrapping runs with foil-backed insulation to stop attic dust infiltration. For east-side two-story homes, it means supporting sagged flex duct spans and sealing torn outer jackets at elbows where dust collects.
You’ll know you need sealing if rooms heat or cool unevenly, your energy bills spike without explanation, or you see dust puffing from registers when the blower starts. In Ontario’s climate, where AC runs eight months a year and Santa Ana winds push desert particulate through every attic vent, unsealed ducts don’t just waste money. They pull that dust straight into your living space.
What the Job Actually Covers
We start with a camera inspection of the full duct run, from plenum to register. Our techs mark every leak point, then seal with duct mastic (a water-based compound that stays flexible and won’t crack like tape alone) and fiberglass mesh tape at joints, takeoffs, and plenum connections. For unwrapped metal runs, we add foil-backed insulation with a proper vapor barrier. For flex duct, we support sagging spans with strapping and replace sections where the inner liner has torn. Post-seal, we run another camera pass and a pressure test to confirm the seal holds.
When Ontario Homes Need It Most
The older your system, the more urgent the need. Original 1950s – 60s metal duct in downtown Ontario tracts was installed before duct sealing was standard practice. By contrast, east-side flex duct from the 1990s – 2000s often fails at support points and elbows where installers rushed the strapping. If your home is 25 years or older and you’ve never had a full duct inspection, you’re likely conditioning your attic instead of your bedrooms.
Duct Sealing Services in Ontario
Duct Sealing Services in Ontario from Hollis cover the full spectrum of leak repair, from spot-sealing accessible joints to whole-system restoration in homes with original unwrapped metal trunkwork. A typical whole-house seal in Ontario’s market runs $450 – $1,200, with simpler spot repairs on newer flex duct starting around $250 – $400. We don’t quote per-vent or per-register. One flat price per system, agreed in writing before work starts.
Our crews carry professional-grade equipment from Nikro and Abatement Technologies, including negative-air containment systems and high-resolution duct cameras that let you see the before and after yourself. We also stock Honeywell and Aprilaire filtration products for Ontario customers who want to upgrade their return-side protection after sealing.
The Garrison Standard on Every Job
Written price before any work starts. Background-checked, uniformed technicians who arrive inside the quoted window. Site left clean. The 365-Day Done Right Promise in writing. These aren’t marketing points. They’re operational requirements for every Hollis crew, enforced because we’ve seen what happens when contractors skip them: prices that balloon, callbacks that go unanswered, attics left trashed.
What We Don’t Do
We don’t sell fogging “sanitiser” treatments as a substitute for sealing. A mist of anti-microbial compound does nothing about open joints pulling attic air, and in Ontario’s dry, dusty climate it can leave residual moisture that promotes microbial growth in duct corners. We also don’t tape outer jackets on sagging flex duct without supporting the span. The tape tears within a season, and you’re back where you started.
What happens when you call
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A real person answersNo phone trees - you reach a local pro.
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You get an upfront price rangeHonest numbers before anyone is dispatched.
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A background-checked tech heads outLicensed & insured, dispatched right away.
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You approve before work beginsNothing starts until you say go.
Trusted Brands We Service in Ontario
Hollis crews seal and repair ductwork connected to all major HVAC brands, and we stock parts and filtration products for fast turnaround on Ontario jobs. Our equipment roster includes Nikro negative-air machines for contained dust control during sealing, plus Honeywell and Aprilaire filtration upgrades for homeowners who want to protect their newly sealed system. For homes with Abatement Technologies HEPA filtration or Guardsman UV systems already installed, we coordinate our seal work to preserve those connections and test post-seal airflow to confirm they’re still performing. Most parts are on the van, so we’re not waiting on a warehouse run while your attic stays open.
Common Duct Sealing Problems We See in Ontario Homes
- Unwrapped 1950s – 60s metal duct south of Holt Blvd. The original round metal supply trunks and branch runs in these downtown and south-Ontario ranches were never sealed at joints or wrapped with insulation. Every blower cycle pulls attic dust and loose fiberglass straight into the supply stream. Sealing only the plenum or a few visible registers leaves the bulk of the leak path wide open.
- Sagged and kinked flex duct in east-side two-story subdivisions. Attic-run flex from the 1980s – 2000s sags between support points and kinks at elbows, creating low spots where dust accumulates and tears where the outer jacket separates. Taping without supporting the span traps debris and guarantees re-tearing within a season.
- Santa Ana wind infiltration through poorly sealed returns. Fall and winter wind events push fine high-desert particulate through attic vents and into return plenums. A seal job done without first removing that accumulated grit leaves it sitting inside the run to be re-entrained on the next blower cycle.
- Fogging upsells sold as sealing substitutes. We regularly encounter Ontario homeowners who paid for an “anti-microbial mist” treatment that did nothing about the actual leak paths. The fogging doesn’t seal joints, doesn’t stop attic air infiltration, and in dry climates can leave moisture that supports growth in corners the mist pooled in.
Pricing for Duct Sealing in Ontario, CA
A typical whole-house duct seal in Ontario runs $450 – $1,200. Spot repairs on accessible flex duct joints start at $250 – $400. Full restoration of original unwrapped metal trunkwork, including mastic sealing, mesh taping, and re-wrapping with foil-backed insulation, runs toward the higher end of that range and occasionally above for very large homes with extensive attic runs.
What moves the price: accessibility (crawlspace versus walk-in attic), extent of original unsealed metal versus newer flex duct, whether we need to support or replace sagged spans, and whether the job includes return-side sealing in addition to supply. We do not quote per-vent. One flat price per system, written down before we start, guaranteed not to change at the door.
Every estimate includes the camera inspection, pre- and post-seal documentation, and our 365-Day Done Right Promise. Call (361) 326-5060 for an exact quote on your Ontario home. Estimates are free.
We Also Serve Cities Near Ontario
Our Inland Empire crews also handle duct sealing in Montclair, Claremont, Upland, and Rancho Cucamonga. Each community has its own housing stock and duct failure patterns, and we adjust our approach accordingly. Whether you’re in Ontario or a neighboring city, the same Garrison Standard applies: written price, written guarantee, crew that shows up squared away.
Serving Ontario, CA - Our Local Coverage Area
We’re based in the Ontario area and know this community well. Use the map below to see our service coverage - if you’re nearby, we can almost certainly help.
FAQs About Duct Sealing in Ontario
You likely need both, but sealing is the priority. In the 1950s – 60s tracts near downtown Ontario and south of Holt Blvd, the original round metal duct was never sealed at joints or wrapped with insulation, so every blower cycle pulls fresh attic dust into your supply stream. Cleaning removes what’s already inside, but without sealing the leak paths, that dust returns within weeks. We typically recommend camera inspection first, then source removal with negative-air containment, followed by mastic sealing and re-wrapping. Call (361) 326-5060 and we’ll walk through what your specific system needs.
No. A fogging treatment does not seal joints, stop attic air infiltration, or address the unwrapped metal runs that are the real problem in older Ontario homes. In our dry, dusty climate, residual moisture from mist treatments can actually promote microbial growth in duct corners where the compound pooled. We don’t sell fogging as a substitute for mechanical sealing. If a contractor tells you misting replaces sealing, get a second opinion. Call (361) 326-5060 for a camera inspection that shows you exactly where your ducts are actually leaking.
The housing stock is completely different. East-side subdivisions built from the 1980s – 2000s use flexible ductboard or flex-duct runs strung through attics, not the rigid metal trunkwork of the 1950s – 60s. Over time, support straps sag, elbows kink, and the outer jacket tears at stress points. The failure mode is physical deformation and jacket separation, not unsealed joints. Our fix involves supporting sagged spans with proper strapping, replacing torn sections, and sealing with mastic and tape rated for flex-duct movement. The older downtown tracts need metal-to-metal sealing and insulation wrapping instead. Call (361) 326-5060 and we’ll tell you which category your home falls into.
Ontario’s location in the Inland Empire dust corridor, combined with Santa Ana wind events that push fine desert particulate through attic vents, means unsealed return plenums and supply leaks accumulate debris faster than in milder climates. If your ducts were sealed more than 10 years ago, or if you’ve never had a full inspection, the original sealant has likely degraded or the support straps have sagged. We recommend a camera inspection every 5 – 7 years for homes with original metal duct, and every 3 – 5 years for flex-duct systems. Call (361) 326-5060 to schedule a look.
Our crews carry Nikro negative-air machines for dust containment during seal work, plus Abatement Technologies HEPA filtration for post-seal air quality protection. We seal with professional-grade duct mastic and fiberglass mesh tape, not hardware-store foil tape that dries and cracks. For homeowners upgrading filtration after sealing, we stock Honeywell and Aprilaire return-air media filters. Every tool on our van is the same equipment commercial crews use, maintained and calibrated. Call (361) 326-5060 for specifics on what we’d recommend for your system.
Written by Roy Castellanos, Owner at Hollis Air Duct Cleaning, serving Ontario and the Inland Empire since 2004.